The present invention describes an oleoresin or lipidic extract of Hypericum perforatum L., which contains hypericine and is enriched with hyperforins, and is stable over time without adding stabilisers. The extract is obtained by extraction with low-polarity solvents and then purification by re-extraction with alcanols-water. The invention describes the use of the oleoresin to regulate the components of the extracellular matrix in a dose dependent manner.
The invention also relates to hydrosoluble gels, the active ingredient of which is Hypericum perforatum L., to be used as cicatrizants.
Hypericum perforatum L has long been used by popular medicine, as a cicatrizant and in the treatment of burns.
The chemical species present in Hypericum perforatum L include acilfloroglucinols: hyperforins and adhyperforins; Hypericum perforatum also contains naptodiantrones: hypericine and pseudohypericine. These compounds are responsible for the activity of the extracts in the treatment of wounds and scars, but these products are unstable when attempting to obtain them in pure form, and over time they decompose due to the effect of light and heat.
European patent EP0854726 describes obtaining stable Hypericum perforatum L extracts by adding antioxidant preservatives such as ascorbic acid, cysteine and/or glutathione, extracting the plant with organic solvents or alcohol-water mixes.
On the other hand, the pharmaceutical formulations described in state of the art DE2406452 are ointments containing an active ingredient consisting of fresh Hypericum leaves and oily excipients (olive oil, bees wax, fatty acid esters, etc.), providing a lipophylic ointment that is insoluble in water.
However, these oily formulations lead to a maceration of the skin after prolonged use, and have a reduced bioavailability making it difficult to wash the lesions, and therefore to monitor their condition.
As mentioned earlier, Hypericum perforatum L extracts have shown different pharmacological activities, mainly as cicatrizants, but to date their effect on the modulation of the extracellular matrix (ECM) of the fibroblasts. The collagen components are therefore responsible for the mechanical properties of the skin, whereas tenascine is responsible for the regulation of the adhesion molecules and migration in cicatrisation processes.
The technical problem of the invention is providing stabilised extracts of Hypericum perforatum L., without adding stable preservatives, without losing its active ingredients and preserving its pharmacological properties. Moreover, its use in a hydrosoluble and stable pharmaceutical composition containing Hypericum perforatum L extract enriched in hyperforins to avoid the maceration of the skin that takes place with treatment with lipophylic ointments and creams, improving bioavailability and the evaluation of the lesions.
Surprisingly, the invention is bases on the stability of the lipidic extracts of Hypericum perforatum L., which contain all its natural components: hyperforins and hypercins, in a lipidic matrix, and are stable over time without adding preservatives. The lipidic extracts or oleoresins are obtained with low-polarity solvents capable of extracting the lipidic components of the drug, followed by purification by re-extraction with alcanols-water.
The extracts have more than 10% content in hyperforins and more than 0.5% in hypericines, in a lipidic matrix that stabilises the active ingredients of Hypericum perforatum L.
The extracts have shown a dose-dependent activity in the regulation of the production of the components of the extracellular matrix, thus avoiding the possible toxicity of the product by inhibiting the production of collagen and tenascine at high doses and, on the other hand, avoiding the formation of hypertrophic and cheloid scars.
The aforementioned extracts can be used in pharmaceutical preparations such as hydrosoluble gels as cicatrizant agents that improve bioavailability, prevent the maceration of the skin, and improve the application of the product compared with the formulations described by the state of the art based on oily or lipophylic excipients. Moreover, with hydrosoluble gels it is possible to better monitor the lesions, since they are transparent.
The invention is based on the stability of Hypericum perforatum L extracts, characterised by the presence of hypericine and hyperforins in a lipidic matrix.
The extracts are obtained first by the extraction of Hypericum perforatum L with a low-polarity solvent, followed by re-extraction with hot alcohol-water mixes, obtaining a fluid oleoresin with over 10% content in hyperforins and more than 0.5% content in hypericines.
The fluid Hypericum perforatum L oleoresins obtained by extraction with low-polarity solvents, followed by hot mixes of alcanols with low molecular weight and water, have been seen to be stable, without losing their hyperforin content due to the effect of light and temperature. The hyperforin content after one year of storage at 40xc2x0 C., exposed to the light and room temperature, has shown a hyperforin content of 15%.
In a preferred embodiment of the invention to prepare the extract, the Hypericum perforatum L is extracted at a low temperature with solvents with a polarity below 0.6. The solvent to be used is not critical, and different mixes can be employed.
The plant is extracted in the proportion of one part drug to 6 parts solvent, by maceration for 24 hours at a temperature less than or equal to 20xc2x0 C. It is then filtered and the drug is extracted again by maceration for 24 hours, and so on until extraction is complete.
The extracts in liquid form are concentrated to obtain a bland and fluid syrup, by high vacuum and a temperature below 40xc2x0 C.
The bland fluid syrup is purified by dissolution in an alcanols-water mix and filtered, preferably using alcohols of low molecular weight, such as methanol, ethanol or isopropanol. The solution is prepared at 40-50xc2x0 C., filtered and concentrated at reduced pressure, obtaining a fluid oleoresin.
With this extraction procedure, the oleoresins obtained have a high content in hyperforins of 10-15% and a content in hypericines of 0.5%, stable over time, determined by chromatographic or spectrophotometric techniques. In order to optimise the extraction procedure, additional steps can be added, such as selecting the initial raw materials with a hyperforin content of over 2%, dehydration of the raw materials at a temperature below 35xc2x0 C., cryogenisation of the plant, etc.
On the other hand, according to the invention, hydrosoluble gels are obtained that facilitate the release of liposoluble Hypericum perforatum L oleoresin, permitting diffusion between the structures of the corneal layer, obtaining more bioavailability than the oily solutions. These hydrosoluble gels contain dilutant, humidifying, gelifying, emulsifying and preservative agents.
In one way of embodying the invention, the preservatives are dissolved in water and the Hypericum perforatum L oleoresin is dissolved in the emulsifiers. This mix is added to the preservatives dissolved in water, followed by the slow addition of the humidifying and gelifying agents, avoiding the occlusion of air.
Preferably water is used as a dilutant, glycerine as a humidifier, glyceril palmitate as a gelifier, parabenes as preservatives and PEG-40-hydrogenated Castor Oil, Polysorbate-20 and Octoxinole-11 as emulsifiers.
The preferred proportions for the invention are as follows:
Hypericum oleoresins regulate the production of the components of the extracellular matrix (ECM) such as collagen and tenastin, but surprisingly, this regulation is dose-dependent.
Hypericum perforatum L oleoresins at low concentrations (0.5-1 xcexcg/ml) increase the production by 70% of the synthesis of collagens in fibroblast cultures, but at concentrations greater than 5 xcexcg/ml, collagen synthesis is inhibited, avoiding the possible toxicity of the product and avoiding the formation of hypertrophic or cheloid scars.
According to the results obtained in the invention, the production of tenascine decreases after the treatment of the fibroblasts with Hypericum oleoresin for 24 h at 37xc2x0 C. in a dose-dependent manner.
Following is a description of the invention using characteristic examples, to which the scope of the invention is not limited.